I'd like to make my screensaver look just like an unlocked desktop.
The idea would be to take a screenshot just before activating the screensaver, and use that screenshot in the screensaver.
Has anyone done this before?
You can use ScriptSaver.
Set the AppleScript to a script containing the following:
do shell script "/usr/sbin/screencapture /path/to/folder/screensaver.png"
/path/to/folder must exist and be empty, or at least contain no other images
Set the screen saver to display after the AppleScript to Classic.
In System Preferences, set the folder for the Classic screensaver to the /path/to/folder.
If you do find a screensaver that can play different images on each display. ( I have my doubts)
Then you can use the screencapture shell command to capture both screens in their own image file.
do shell script "/usr/sbin/screencapture -R\"0,0,2560,1440\" /path/to/folder/screensaver1.png;/usr/sbin/screencapture -R\"2558,0,4480,12000\" /path/to/folder/screensaver2.png"
The -R option "x,y,width,height" will capture screen rect.
To get both displays in one image.
do shell script "/usr/sbin/screencapture -R\"0,0,4480,1200\" /path/to/folder/screensaver3.png"
This seems to do exactly what you want. I use it to secure a machine that shows a dashboard. It works great.